ABSTRACT
This chapter focuses on several relevant physical concepts, ranging from unwanted antennas to unexpectedly high-impedance grounds and imperfect shielding. The mystification of Electromagnetic Interference (EMI) arises from two sources. First, solutions can be obtained analytically only for the simplest geometries, such as a wire above a plane or a circular loop of wire. Whenever a device deviates from these easily described geometries, EMI problems become unsolvable using standard circuit or field analysis techniques. Second, there are almost always two or more interference problems existing in concert. There may be multiple sources of interference, multiple receptors, and multiple paths connecting the interference sources to the receptors. Moreover, the connecting paths may be either conducted or radiated, or a combination of the two. All of these different variations need to be considered before the problems can be controlled or eliminated.
